Predictors of survival for infants with congenital diaphragmatic hernia

Over the past decade, the survival rate of infants with congenital diaphragmatic hernia (CDH) treated in the intensive care unit of the Royal Children's Hospital, Melbourne, has remained unchanged at 56% ± 6%. Newer forms of treatment, such as extracorporeal membrane oxygenation (ECMO), high-frequency oscillation, and surfactant and nitric oxide therapy, are now available. The exact role of these therapies in the management of infants with CDH has not been determined. This study examines five clinical parameters derived from an infant's best preoperative ventilatory and blood gas data in the first 24 hours of life. One hundred twenty-five CDH infants were admitted to the intensive care unit between January 1, 1981 and December 31, 1991. Criteria for inclusion in the study were (1) CDH diagnosed within 6 hours of delivery, (2) ventilation before repair, and (3) no associated lethal congenital abnormality. Of the 90 cases studied in detail, there were 38 deaths (42% mortality rate). All five parameters were analyzed by receiver operating curve analysis to determine the optimum value of each parameter in predicting survival. An oxygenation index ( MAP × Fio 2 Pao 2 ) of less than 0.08 predicted a 94% chance of survival, with a sensitivity of 96% and a specificity of 95%. Similarly, a modified ventilation index ( PIP × RR × CO 2 1,000 ) of less than 40 predicted a 91% chance of survival, with a sensitivity of 94% and a specificity of 86%. By stratifying each criterion according to outcome, three groups of infants were identified according to their response to conventional therapy. There is a large group of infants that can be expected to survive with conventional therapy and are likely to have minimal pulmonary hypoplasia. A second group can be expected to die with use of conventional therapy; this group may well represent infants with severe pulmonary hypoplasia who are unlikely to benefit from therapies designed to combat pulmonary hypertension or minimize lung barotrauma. Between these two groups is a small group of infants whose outcome from conventional therapy is less predictable. We believe that this group may represent infants with significant pulmonary hypertension and moderate pulmonary hypoplasia. These patients may benefit from newer therapies that treat pulmonary hypertension and minimize lung injury.